Blender: on/off collision modifier
Typically you can animate any value in blender by hitting i. If there isn't an on/off switch, you can modify the collision object's geometry.

Go to the frame before the shattering. There hit i > Scale. Go to the next frame and sto scale the object up. Make it so big that it doesn't block the flow of the fluid. i > Scale again to save the size.

Now it should work.